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pmap_enter_quick_locked() never replaces a valid mapping, so it need not

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perform a TLB invalidation.  A barrier suffices.  (See r343876.)

Add a comment to pmap_enter_quick_locked() in order to highlight the
fact that it does not replace valid mappings.

Correct a typo in one of pmap_enter()'s comments.

MFC after:	1 week
This commit is contained in:
Alan Cox 2019-06-23 21:06:56 +00:00
parent 01e92e2977
commit 22c7bcb842
1 changed files with 5 additions and 2 deletions
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7
sys/arm64/arm64/pmap.c
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@ -3408,7 +3408,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
__func__, pmap, va, new_l3);
}
} else {
/* New mappig */
/* New mapping */
pmap_load_store(l3, new_l3);
dsb(ishst);
}
@ -3706,6 +3706,9 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
l3 = pmap_l2_to_l3(pde, va);
}
/*
* Abort if a mapping already exists.
*/
if (pmap_load(l3) != 0) {
if (mpte != NULL) {
mpte->wire_count--;
@ -3755,7 +3758,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
cpu_icache_sync_range(PHYS_TO_DMAP(pa), PAGE_SIZE);
pmap_load_store(l3, l3_val);
pmap_invalidate_page(pmap, va);
dsb(ishst);
return (mpte);
}